1. Field of the Invention
The present invention relates to a drive (which is also called a driving device) using a shape-memory alloy.
2. Description of the Background Art
There are shape-memory alloys which have the property of changing their shapes with temperature. Also, there is a well-known drive that has a drive mechanism composed of a drive member of rod-like (or linear) shape-memory alloy (which is also referred to as a shape-memory member) and that achieves drive by controlling the amount of current applied to the shape-memory member (Japanese Patent Application Laid-open No. 2001-170900). In this drive, the ends of the shape-alloy member are crimped by crimp terminals to a moving part of the drive.
Use of such a drive as disclosed in Japanese Patent Application Laid-open No. 2001-170900 in environments that require agility in operation necessitates improvement in the response speed of the drive by reducing the diameter (sectional diameter) of the shape-memory member.
However, a smaller diameter of the shape-memory member results in lower holding power provided by crimping between the shape-memory member and the crimp terminal, thereby causing a problem of inability to stand operating environments as above described.
Besides, in order to ensure stable operation with the drive as disclosed in Japanese Patent Application Laid-open No. 2001-170900 in operating environments that require a large driving force, it is generally required to improve holding power between the shape-memory member and the crimp terminal.